Opportunistic progressive encoding

ABSTRACT

Methods, systems, and devices are described for communicating data from multiple data terminals to an aggregator terminal over a communication link having changing link conditions. In some embodiments, source data is received at multiple data terminals, each in communication with an aggregator terminal over a communication link. For example, during a live newscast, one mobile camera may receive live video of an event from a first position while another mobile camera receives live video of the event from a second position. For various reasons (e.g., as the cameras move) each communication link may experience independently changing link conditions. Each data terminal encodes the source data (or store source data for later encoding) as a function of its respective link conditions, and transmits encoded source data over its respective communication link to the aggregator terminal.

CROSS REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 15/842,588, filed on Dec. 14, 2017, and entitled,“OPPORTUNISTIC PROGRESSIVE ENCODING,” which is a continuation of U.S.patent application Ser. No. 14/688,767, filed on Apr. 16, 2015, andentitled, “OPPORTUNISTIC PROGRESSIVE ENCODING,” which is a continuationof U.S. patent application Ser. No. 13/310,575, filed on Dec. 2, 2011,and entitled, “LINK AWARE MOBILE DATA NETWORK,” which is a divisional ofU.S. patent application Ser. No. 12/192,544, filed on Aug. 15, 2008, andentitled, “LINK AWARE MOBILE DATA NETWORK,” which iscontinuation-in-part of U.S. patent application Ser. No. 11/956,200,filed on Dec. 13, 2007, and entitled, “ACM AWARE ENCODING SYSTEMS ANDMETHODS,” which claims priority to Provisional Application No.60/869,809, filed on Dec. 13, 2006, and entitled, “ADAPTIVE CODING &MODULATION (ACM) AWARE ENCODER SYSTEM.” which are hereby incorporated byreference, as if set forth in full in this document, for all purposes.

BACKGROUND

The present invention relates to data communications in general and, inparticular, to link-aware adaptive communications networks.

Data networks may use multiple data terminals to simultaneously collectdata from multiple sources in multiple locations and aggregate the dataat a base location. For example, during a newscast, a mobile productionstation (e.g., a specially outfitted truck) may aggregate video, audio,text, and other data from geographically distributed cameras,microphones, newswires, databases, etc. When some or all of these dataterminals communicate with the base location wirelessly, changing linkconditions (e.g., changes in weather) may result in changing dataconditions (e.g., changes in data quality, latency, etc.).

Various techniques may dynamically adjust pre-coding, coding, and/ormodulation schemes to adapt to these changing link conditions. Forexample, as link conditions worsen, the integrity of data beingcommunicated over those links may be increased or maintained by usingmore reliable (lower order) coding and modulation schemes. Without anawareness of the link conditions, however, it may not be possible tofully exploit these and other adaptive techniques.

Thus, there may be a general need in the art for providing dataterminals and aggregator terminals having link awareness and adaptationcapabilities.

SUMMARY

Among other things, methods, systems, and devices are described forproviding data terminals and aggregator terminals having link awarenessand adaptation capabilities.

In some embodiments, source data (e.g., a video stream) is received atmultiple data terminals, each in communication with an aggregatorterminal over a communication link. Each communication link mayexperience changing link conditions and likely has different linkconditions from other communication links. Each of the data terminalsencodes the source data as a function of the link conditions associatedwith its respective communication link (e.g., current link conditions,predicted link conditions, past link conditions, etc.). At least aportion of the encoded source data is communicated over its respectivecommunication link to an aggregator terminal. In certain embodiments,the aggregator terminal is adapted to receive and aggregate multipleencoded data streams from the multiple data terminals. The aggregatorterminal may have additional functionality, like dynamic buffering. Incertain embodiments, the aggregator terminal is further adapted tomonitor and/or control operation of some or all of the data terminals,for example as a function of changing link conditions.

In one set of embodiments, a link-aware data system is provided forcommunicating data between multiple data terminals and an aggregatorterminal over communication links with changing link conditions. Thesystem includes an aggregator unit, adapted to receive data over aplurality of communication links and aggregate the data into anaggregate dataset; and a plurality of data terminals, eachcommunicatively coupled with the aggregator unit via at least one of theplurality of communication links. Each data terminal includes a receiverunit adapted to receive source data from a data source; a link awarenessunit adapted to generate a link condition defining a condition of the atleast one of the plurality of communication links; an adaptive coderunit, communicatively coupled with the receiver unit and the linkawareness unit, and adapted to encode the source data into an encodeddata signal as a function of the link condition; and a transceiver unit,communicatively coupled with the adaptive coder unit, and adapted totransmit the encoded data signal over the at least one of the pluralityof communication links, wherein the aggregator unit is adapted toreceive data by receiving the encoded data signal over the at least oneof the plurality of communication links.

In another set of embodiments, a method is provided for receiving sourcedata and transmitting the source data over a communication link havingchanging link conditions. The method includes storing at least a portionof the source data as a first representation dataset representing thesource data; pre-coding at least a portion of the source data using afirst pre-coding scheme to generate a second representation dataset,decodable to provide a set of first-level playback data representing thesource data, the second representation dataset being different from thefirst representation dataset; generating a link condition defining acondition of the communication link; encoding the second representationdataset into an encoded data signal as a function of the link condition;and transmitting the encoded data signal over the communication link.

In yet another set of embodiments, a link-aware data system is providedfor receiving source data and transmitting the source data over acommunication link having changing link conditions. The system includesa receiver unit adapted to receive the source data from a data source; alink awareness unit adapted to generate a link condition defining acondition of the communication link; an adaptive coder unit,communicatively coupled with the receiver unit and the link awarenessunit, and adapted to encode the source data into an encoded data signalas a function of the link condition; and a transceiver unit,communicatively coupled with the adaptive coder unit, and adapted totransmit the encoded data signal over the communication link.

In still another set of embodiments, a method is provided for adaptivelyaggregating data received over communication links having changing linkconditions. The method includes receiving a first encoded data signalfrom a first data system over a first communication link, the firstencoded data signal being encoded by the first data system using a firstencoding scheme as a function of a first link condition defining acondition of the first communication link; receiving a second encodeddata signal; aggregating at least a portion of the first encoded datasignal and at least a portion of the second encoded data signal togenerate an aggregate dataset; analyzing the aggregate dataset to make adata deficiency determination; generating a control signal as a functionof the data deficiency determination; and transmitting the controlsignal to the first data system, the control signal being adapted toaffect operation of the first data system.

In even another set of embodiments, a system is provided for adaptivelyaggregating data from a plurality of remote data terminals overcommunication links having changing link conditions. The system includesa first receiver unit, adapted to receive a first encoded data signalfrom a first data system over a first communication link, the firstencoded data signal being encoded by the first data system using a firstencoding scheme as a function of a first link condition defining acondition of the first communication link; a second receiver unit,adapted to receive a second encoded data signal from a second datasystem over a second communication link, the second encoded data signalbeing encoded by the second data system using a second encoding schemeas a function of a second link condition defining a condition of thesecond communication link; and an analyzer unit, communicatively coupledwith the first receiver unit and the second receiver unit, and adaptedto generate an aggregate dataset as a function of data from the firstencoded data signal and data from the second encoded data signal.

And in another set of embodiments, a computer-readable storage medium isprovided having a computer-readable program embodied therein fordirecting operation of a link-aware data terminal, the computer-readableprogram including instructions for receiving source data andtransmitting the source data over a communication link having changinglink conditions. The computer-readable program instructions are inaccordance with the following: storing at least a portion of the sourcedata as a first representation dataset representing the source data;pre-coding at least a portion of the source data using a firstpre-coding scheme to generate a second representation dataset, decodableto provide a set of first-level playback data representing the sourcedata, the second representation dataset being different from the firstrepresentation dataset; generating a link condition defining a conditionof the communication link; encoding the second representation datasetinto an encoded data signal as a function of the link condition; andtransmitting the encoded data signal over the communication link.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the following drawings. In theappended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel, or a lower-case character, that distinguishes among the similarcomponents. If only the first reference label is used in thespecification, the description is applicable to any one of the similarcomponents having the same first reference label irrespective of thesecond reference label.

FIG. 1 shows a simplified block diagram of a link-aware datacommunication and aggregation system, according to various embodimentsof the invention.

FIG. 2 shows a simplified block diagram of a satellite communicationsystem for use with various embodiments of the invention.

FIG. 3 provides a simplified block diagram of an embodiment of a dataterminal, configured according to various embodiments of the invention.

FIG. 4 provides a simplified block diagram of an embodiment of anaggregator terminal, according to various embodiments of the invention.

FIG. 5A shows a functional block diagram incorporating a pre-coder unit,according to various embodiments of the invention.

FIG. 5B provides a functional block diagram of a set of embodimentsincorporating a pre-coder unit using scalable pre-coding schemes,according to various embodiments of the invention.

FIG. 5C provides a functional block diagram illustrating a set ofembodiments of a pre-coder unit using data partitioning pre-codingschemes, according to various embodiments of the invention.

FIG. 5D provides functional block diagram of a set of embodimentsincorporating a pre-coder unit using hybrid scalable and datapartitioning pre-coding schemes, according to various embodiments of theinvention.

FIG. 6 provides an illustration of an exemplary table of identifier datafor use with various embodiments of the invention.

FIG. 7 provides a functional block diagram of a device incorporating aprocessor unit, a representation data store, and an identifier datastore, according to various embodiments of the invention.

FIG. 8A provides a functional block diagram incorporating a processorunit, according to various embodiments of the invention.

FIG. 8B, provides another functional block diagram incorporating aprocessor unit, according to various embodiments of the invention isprovided.

FIG. 9A provides an exemplary embodiment illustrating adapting codingand modulation schemes to link conditions, according to variousembodiments of the invention.

FIG. 9B provides another exemplary embodiment illustrating adaptingcoding and modulation schemes to link conditions, according to variousembodiments of the invention.

FIG. 10 shows an illustrative computational system for providing linkaware communications in over communication links with changing linkconditions, according to various embodiments of the invention.

FIG. 11 provides a flow diagram describing methods for receiving sourcedata and transmitting the source data over a communication link havingchanging link conditions, according to various embodiments of theinvention.

FIG. 12 provides a flow diagram describing methods for aggregating datareceived over communication links having changing link conditions,according to various embodiments of the invention.

DETAILED DESCRIPTION

This description provides exemplary embodiments only, and is notintended to limit the scope, applicability or configuration of theinvention. Rather, the ensuing description of the embodiments willprovide those skilled in the art with an enabling description forimplementing embodiments of the invention. Various changes may be madein the function and arrangement of elements without departing from thespirit and scope of the invention.

Among other things, the description provides methods, systems, software,and devices for transmitting source data from multiple data terminals toan aggregator terminal over communication links having changing linkconditions. Turning first to FIG. 1, a simplified block diagram of alink-aware data communication and aggregation system is provided,according to various embodiments of the invention. The system 100includes a number of mobile data terminals 120 and a number of fixeddata terminals 130, all communicatively coupled with an aggregatorterminal 110.

In some embodiments, source data is received at each of the multipledata terminals, including the mobile data terminals 120 and the fixeddata terminals 130. Embodiments of source data may include audio, video,and/or any other type of media or non-media data. Further, source datamay be received live, streaming, stored, raw, encoded, or in any otheruseful form. For example, video source data may include a scene fromwhich live video may be received, a live video stream being streamedfrom another device or network, a stored video stream being receivedfrom a data store (e.g., a tape, drive, server, etc.), etc.

It will be appreciated that the mobile data terminals 120 and fixed dataterminals 130 may include any devices, systems, components, and/orsoftware capable of receiving source data and communicating the sourcedata to the aggregator terminal 110. In one illustrative embodiment, anumber of mobile data terminals 120 and fixed data terminals 130 areused to generate and receive data relating to an automobile racingevent. Multiple mobile cameras (e.g., in various cars, on remotedollies, etc.) may be used as mobile data terminals 120 for receivinglive video feeds of the event from various locations and angles, astationary newscaster (e.g., in an announcer's booth) and a sidelinecameraman may have fixed cameras for use as fixed data terminals 130, aremote server may be used as a fixed data terminal 130 from which toreceive archive footage, and a geosynchronous satellite may be used as afixed data terminal 130 for receiving weather information. The sourcedata from each of these mobile data terminals 120 and fixed dataterminals 130 may be sent to an aggregator terminal 110 for aggregationand/or production.

Certain of the mobile data terminals 120 and/or fixed data terminals 130may communicate with the aggregator terminal 110 over communicationlinks 102 having changing link conditions (e.g., communication link102-1), while others may communicate with the aggregator terminal 110over communication links 102 having stable or fixed link conditions(e.g., communication link 102-2). Link conditions may include any typeof parameter associated with a communication link that may affect thecommunication of data over the link. For example, a communication linkmay be characterized by its bandwidth, signal-to-noise ratio, bit errorrate, power level, data traffic priority, data traffic protocol,latency, cost-per-bit, etc. Notably, some or all of these linkconditions may change over time. For example, a changing geographiclocation of a mobile data terminal 120 relative to the aggregatorterminal 110 may affect the signal-to-noise ratio and latency of acommunication link between them.

Embodiments of the mobile data terminals 120 and/or fixed data terminals130 may be adapted to encode the source data as a function of the linkconditions (e.g., current link conditions, predicted link conditions,past link conditions, etc.). For example, as a mobile data terminal 120moves, its link condition may change so as to adversely affect dataintegrity over a communication link between the mobile data terminal 120and the aggregator terminal 110. The mobile data terminal 120 may beadapted to at least partially counteract this effect by using adifferent encoding scheme (e.g., a higher order encoding scheme, asdescribed below).

In some embodiments, the mobile data terminals 120 and/or fixed dataterminals 130 are further adapted to store some or all of the sourcedata (e.g., in a drive, server, buffer, etc.). The stored source datamay be encoded for transmission at a different time or under differentlink conditions. In certain embodiments, certain, more critical elementsof the received source data are encoded using a first encoding schemeand transmitted to the aggregator terminal 110 using a high-reliabilitytransmission scheme. Other, less critical elements of the receivedsource data may be stored, encoded, and or transmitted differently. Forexample, less critical source data elements may be transmitted onlyunder certain link conditions, transmitted using lower-reliabilitytransmission schemes, encoded using different encoding schemes, etc.

For example, say a mobile data terminal 120 transmits a down-convertedportion of its received source data to compensate for undesirable linkconditions substantially at the time the source data is received. In oneembodiment, the down-converted data is insufficient to generateproduction-quality video data, but is sufficient to provide certainother information (e.g., blocking of the scene, audio from the scene,positions of certain objects or people in the scene, general colorbalance information, timing information, etc.). For example, it may bepossible to begin blocking out video footage, storyboards, and otherproduction-related tasks using the down-converted data. In anotherembodiment, the down-converted data is sufficient for generating alow-resolution video feed (e.g., for use on cellular telephone screens,standard-definition televisions, etc.), but is insufficient forproviding a high-resolution video feed (e.g., for use on high-definitiontelevisions, very large displays, etc.).

In these and other embodiments, at certain times or over a period oftime, additional data may be transmitted to the aggregator terminal 110from some or all of the mobile data terminals 120 or fixed dataterminals 130. In one embodiment supplemental elements from the sourcedata may be transmitted over time to the aggregator terminal 110 to beaggregated with previously transmitted elements from the source data.For example, high-definition elements may be transmitted to theaggregator terminal 110 to fill in previously transmitted low-definitionelements from a particular set of source data. Where the high-definitionelements are less critical, they may be transmitted accordingly (e.g.,by using lower-reliability transmission schemes).

In some embodiments, the aggregator terminal 110 is adapted to monitorand/or control operation of some or all of the mobile data terminals 120and/or fixed data terminals 130. In certain embodiments, the aggregatorterminal monitors deficiencies in the incoming data and transmitscontrol signals to the mobile data terminals in an attempt to resolvethose data deficiencies. It will be appreciated that data deficienciesmay include any type of information gained from analyzing the aggregatedataset to determine what other data may be necessary or desirable. Forexample, data deficiencies may include unusable data (e.g., data that ismissing, incorrect, corrupt, incompatible, etc.), missing or deficientsource data content (e.g., missing viewpoints or angles, bad lighting,missing source data elements that may or may not be stored at a dataterminal), etc.

In one embodiment, the aggregator terminal 110 determines that dataoriginating from a particular mobile data terminal 120-2 is not beingreceived at the aggregator terminal 110 with desirable integrity. Theaggregator terminal 110 may generate a control signal and transmit thecontrol signal to the particular mobile data terminal 120-2, causing theparticular mobile data terminal 120-2 to adjust its encoding scheme toachieve better data integrity over the communication link. In anotherembodiment, the aggregator terminal 110 determines that data originatingfrom the particular mobile data terminal 120-2 is using too wide of afield of view setting (e.g., according to some automatic algorithmicdetermination or according to some manual human determination). Theaggregator terminal 110 may generate a control signal and transmit thecontrol signal to the particular mobile data terminal 120-2, causing theparticular mobile data terminal 120-2 to adjust its field-of-viewsetting (e.g., either automatically in response to the control signal orby informing the operator of the particular mobile data terminal 120-2to make the change).

It will be appreciated that embodiments of the aggregator terminal 110may be adapted to monitor and/or control operation of the mobile dataterminals 120 and/or fixed data terminals 130 in any useful way. It willbe further appreciated that the aggregator terminal 110 may be adaptedto provide additional functionality. For example, embodiments of theaggregator terminal 110 may include functionality for data processing,data production, data storage, data transmission, interfacing withoperators and other systems, etc.

In certain embodiments, one or more mobile data terminals 120 and/orfixed data terminals 130 may communicate with the aggregator terminal110 through one or more intermediaries. For example, a localizedsub-aggregator terminal 140 may receive data and retransmit the data tothe aggregator terminal 110. It will be appreciated that thesub-aggregator terminal 140 may include some or all of the functionalityof the mobile data terminals 120, fixed data terminals 130, and/oraggregator terminal 110.

It will be appreciated that many types of networks may providecommunication links with changing link conditions, according to variousembodiments of the invention. Further, it will be appreciated that alink-aware system may be able to adjust (e.g., compensate) as a functionof changes in link conditions in a number of ways, according to variousembodiments of the invention. By way of illustration, FIGS. 2-11describe some of the various systems and methods according toembodiments of the invention for link-aware encoding in a communicationsystem.

FIG. 2 shows a simplified block diagram of a satellite communicationsystem for use with various embodiments of the invention. While asatellite communication system is used to illustrate various aspects ofthe invention, it is worth noting that certain principles set forthherein are applicable to a variety of other wireless systems, as well.The satellite communications system 200 includes an aggregator station215 (e.g., the aggregator terminal 110 of FIG. 1) that is configured tocommunicate with one or more data terminals 230 (e.g., the mobile dataterminals 120 and/or the fixed data terminals 130 of FIG. 1) via asatellite 205.

In some embodiments, the aggregator station 215 is included in a mobilebase station 220 (e.g., a truck) that maintains a connection with thesatellite network 200. Embodiments of the aggregator station 215 may beconfigured to receive data and information directed to one or more dataterminals 230, and can format the data and information for delivery tothe respective data terminal 230 via the satellite 205. Similarly, theaggregator station 215 may be configured to receive signals from thesatellite 205, including, but not limited to encoded data from one ormore data terminals 230.

In some embodiments, the data terminals 230 use adaptive coding andmodulation (“ACM”) to generate layered transmissions of information tothe aggregator station 215. ACM may allow the satellite communicationsystem 200 to dynamically adjust the coding and modulation schemesapplied to transmissions to adapt to changing link conditions. Lowerorder coding and modulation schemes may use lower order modulation andlower information densities to provide more reliable transmission ofinformation over the communication link. Thus, while lower order codingand modulation schemes may be more reliable, they may also be lessbandwidth efficient (e.g., less information may be transmitted per unitbandwidth per unit time). This may mean that, in order to maintain theavailability or integrity of communications over the satellitecommunication network 200 in changing link conditions, the amount ofinformation transmitted over a communication link per unit time may bedynamic.

Table 1 (below) provides a purely exemplary set of data to furtherclarify the trade-off between availability and bandwidth efficiency. Assuch, the data in Table 1 should not be construed as limiting the scopeof the invention. Referring to Table 1, the leftmost column shows theavailability of an exemplary communication system ranging from 99% to99.99%. The remaining columns, from left to right, show metrics relatingto the link margin, signal-to-noise ratio, coding and modulation scheme,and bandwidth efficiency of the exemplary communication system,respectively. As illustrated by Table 1, lower order coding andmodulation schemes are used to increase availability of the network(i.e., the coding and modulation scheme is changed from 16APSK 3/4 toQPSK 3/4 to increase availability from 99% to 99.99%). The illustrativeresult shows a decrease in bandwidth efficiency from 2.97 to 1.32,almost a 60% decrease in bandwidth efficiency.

TABLE 1 Availability vs. Bandwidth Efficiency Operating Selected CodingLink Margin Es/No and Modulation Bandwidth Availability (dB) (dB) SchemeEfficiency  99% 0.53 10.67 16APSK 3/4 2.97 99.9% 2.33 8.87   8PSK 3/42.23 99.99%  7.19 4.01  QPSK 3/4 1.32

In some embodiments, the aggregator station 215 may further usehierarchical pre-coding schemes at least in part to mitigate thetrade-off between availability and bandwidth efficiency. In certainembodiments, hierarchical pre-coding schemes may include simulcasting(simultaneously broadcasting) multiple versions of a set of source data(e.g., standard- and high-definition versions of a video stream). Inother embodiments, hierarchical pre-coding schemes may include scalablepre-coding schemes, data partitioning schemes, and other pre-codingschemes, as described below. In certain embodiments, the hierarchicallypre-coded data may be adaptively coded and/or modulated for transmissionover the communication link in a layered fashion. In this way, it may bepossible to affect either or both of availability and bandwidthefficiency per each hierarchical data layer, adding flexibility to thesatellite communication system 200.

In certain embodiments, the aggregator station 215 and/or data terminals230 may use either or both of ACM and hierarchical pre-coding schemes.In one example, multiple hierarchical layers are created, but a singlecoding and modulation scheme is used for all the layers. In anotherexample, a single layer may be sent using multiple coding and modulationschemes. In other embodiments, the aggregator station 215 and/or dataterminals 230 may pre-code, code, and/or modulate only a portion of thedata. For example, a data terminal 230-1 may detect that only enoughbandwidth is available to transmit a single layer over the communicationlink. In this case, it may be efficient for the data terminal 230-1 togenerate only a single layer for some or all of the incoming sourcedata.

Source data (e.g., IP datagrams, video feeds, etc.) may be communicatesfrom one or more data terminals 230 to the aggregator station 215. Avariety of physical layer transmission modulation and coding techniquesmay be used with certain embodiments of the invention, including thosedefined with the DVB-S2 and WiMAX standards. In a number of embodiments,the data terminals 230 utilize ACM in conjunction with one or morehierarchical data pre-coding schemes described herein to direct trafficto the aggregator station 215.

The aggregator station 215 may also use various techniques tocommunicate with one, a subset, or all of the data terminals 230. In oneembodiment, the aggregator station 215 uses a broadcast signal, with amodulation and coding format adapted for each packet to the linkconditions of the terminal 230 or set of terminals 230 to which thepacket is directed (e.g., to account for the variable downlink 250conditions from the satellite 205 to each respective terminal 230). Inother embodiments, other techniques (e.g., unicast, multicast, etc.)and/or other protocols are used.

The aggregator station 215 may use an antenna 210 to communicate withthe satellite 205. In one embodiment, the antenna 210 includes aparabolic reflector with high directivity in the direction of thesatellite and low directivity in other directions. The antenna 210 maybe implemented in a variety of alternative configurations. Certainsignals may include, for example, a number of single carrier signals.Each signal carrier signal may be divided (e.g., using Time DivisionMultiple Access (“TDMA”)) into a number of virtual channels. The virtualchannels may be the same size, or different sizes. In other embodiments,other channelization schemes may be used, such as Frequency DivisionMultiple Access (“FDMA”), Orthogonal Frequency Division Multiple Access(“OFDMA”), Code Division Multiple Access (“CDMA”), or any number ofhybrid or other schemes known in the art. Embodiments of the dataterminals 230 are also adapted to use antennae 225 to communicate withthe satellite 205. The antennae 225 of the data terminals 230 may be thesame as or different from each other and/or the antenna 210 of theaggregator station 215.

In one embodiment, a geostationary satellite 205 is configured toreceive the signals from the antenna (210 or 225) and within thefrequency band and specific polarization transmitted. The satellite 205may process received signals, forwarding signals received from theaggregator station 215 to one or more data terminals 230, and forwardingsignals received from the one or more data terminals 230 to theaggregator station 215. In some embodiments, only a portion of the dataterminals 230 may be able to send and/or receive some or all of thesignals due to certain link conditions.

In another embodiment, the satellite 205 operates in a multi-beam mode,transmitting a number of narrow beams each directed at a differentregion of the earth, allowing for frequency re-use. This satellite 205may be configured as a “bent pipe” satellite, wherein the satellite 205may frequency convert the received carrier signals before retransmittingthese signals to their destination, but otherwise perform little or noother processing on the contents of the signals. A variety of physicallayer transmission modulation and coding techniques may be used by thesatellite 205 in accordance with certain embodiments of the invention,including those defined with the DVB-S2 and WiMAX standards. For otherembodiments, a number of configurations are possible (e.g., using LEOsatellites, or using mesh networks instead of star networks), as knownin the art.

The service signals 250 transmitted from the satellite 205 may bereceived by one or more data terminals 230, via the respectivesubscriber antenna 225. The data terminals 230 may send/receive thesignals to/from the satellite 205 under very diverse link conditions. Incertain embodiments, the data terminals 230 may encode sent signalsand/or decode received signals differently based on different linkconditions.

In one embodiment, the antenna 225 and terminal 230 together comprise avery small aperture terminal (“VSAT”). In other embodiments, a varietyof other types of antennas 225 may be used at the subscriber terminal230 to send/receive a signal. Each of the data terminals 230 maycomprise a single user terminal or, alternatively, a hub or router (notpictured) that is coupled to multiple user terminals.

In one embodiment, a Multi-Frequency TDMA (“MF-TDMA”) scheme is used forsome links (e.g., 240 and 245), allowing efficient streaming of trafficwhile maintaining flexibility in allocating capacity among each of thedata terminals 230. In this embodiment, a number of frequency channelsare allocated which may be fixed, or which may be allocated in a moredynamic fashion. A TDMA scheme is also employed in each frequencychannel. In this scheme, each frequency channel may be divided intoseveral timeslots that can be assigned to a connection (i.e., asubscriber terminal 230). In other embodiments, one or more links may beconfigured with other schemes, such as FDMA, OFDMA, CDMA, or any numberof hybrid or other schemes known in the art.

A subscriber terminal 230 may transmit information related to signalquality to the aggregator station 215 via the satellite 205. The signalquality may be a measured signal to noise ratio, an estimated signal tonoise ratio, a bit error rate, a received power level, or any othercommunication link quality indicator. The subscriber terminal 230 itselfmay measure or estimate the signal quality, or it may pass informationmeasured or estimated by other devices. This signal quality informationmay be used by the aggregator station 215 in some embodiments to adaptdecoding, aggregation, pre-coding schemes, and/or coding and modulationschemes to match link conditions. Similarly, in some embodiment, theaggregator station 215 may transmit control signals and/or informationrelated to signal quality to one or more data terminals 230 via thesatellite 205. It is worth noting that the aggregator station 215 andthe data terminals 230 may communicate according to a variety ofphysical layer transmission modulation and coding techniques, includingthose defined with the DVB-S2 and WiMAX standards. In variousembodiments, the physical layer techniques may be the same for each ofthe links 235, 240, 245, 250, or may be different.

The functions of the components of the satellite communication system200 may be implemented in a number of different ways. For example, someor all of the functionality of the aggregator station 215 and/or thedata terminals 230 may be implemented in other components of the system,for example in the satellite 205. Further, many embodiments ofaggregator stations 215 and data terminals 230 are possible according tothe invention.

FIG. 3 provides a simplified block diagram of an embodiment of a dataterminal 320 configured according to various embodiments of theinvention. In some embodiments, the data terminal 320 is similar to someor all of the mobile data terminals 120 of FIG. 1, the fixed dataterminals 130 of FIG. 1, or the data terminals 230 of FIG. 2. It isworth noting that the functionality of the data terminal 320 may beimplemented in any number of different ways.

In some embodiments, the data terminal 320 includes a receiver unit 324,a link-adaptive coder unit 336, and a transceiver unit 344. The dataterminal 320 may receive a set of source data 310, process the sourcedata 310 using various components (including the link-adaptive coderunit 336), and transmit the data over a communication link 360 using thetransceiver unit 344.

In some embodiments, the data terminal 320 includes the receiver unit324, which receives the set of source data 310. The set of source data310 may include, for example, audio data, video data, voice data, or anyother type of data. The receiver unit 324 may include any hardware,software, or other components necessary to receive the set of sourcedata 310. For example, the receiver unit 324 may include amplifiers,buffers, ports, codecs, etc. In one embodiment, the set of source data310 includes an audio-visual data stream, which is received by thereceiver unit 324 from a data source (e.g., a network, a data store,etc.) through a data port. In another embodiment, the set of source data310 is received live by the receiver unit 324 (e.g., via a camera,microphone, and/or other sensor device).

In some embodiments, the receiver unit 324 passes all or a portion ofthe set of source data 310 directly to the link-adaptive coder unit 336.In other embodiments, the receiver unit 324 passes all or a portion ofthe set of source data 310 to one or more intermediate components. Inone embodiment, the source data 310 is received by the receiver unit 324in an undesirable format (e.g., a format that is incompatible withcertain functionality of the link-adaptive coder unit 336). It may bedesirable to transcode the received source data 310 into a differentformat, using a transcoder unit 328, prior to passing the data to thelink-adaptive coder unit 336.

In another embodiment, source data 310 may be received faster (or at adifferent time) than processing takes place by the link-adaptive coderunit 336 and/or the transcoder unit 328. For example, complex algorithmsthat may be used by the link-adaptive coder unit 336 may cause thelink-adaptive coder unit 336 to process data more slowly than it isreceived by the receiver unit 324. As such, it may be desirable tobuffer data as it is received. For this and other reasons, embodimentsof the data terminal 320 may include a buffer unit 332 for buffering allor part of the received source data 310. Data may then be passed fromthe buffer unit 332 to the link-adaptive coder unit 336 for furtherprocessing.

After or while the link-adaptive coder unit 336 receives data, it maypre-code the data to generate sets of representation data. The sets ofrepresentation data may contain any type of information, includinginformation extracted or adapted from the set of source data 310 thatmay be useful for generating a representation of the set of source data310. For example, a set of representation data may contain enoughinformation extracted from a source video stream to allow the generationof a lower-resolution version of the video stream. In another example,the set of representation data may include color or texture information,which may be added to other sets of representation data to generate anenhanced version of the source video stream.

In certain embodiments, the link-adaptive coder unit 336 applies certainpre-coding schemes, including scalable pre-coding schemes, datapartitioning schemes, etc. In one embodiment, where the set of sourcedata 310 includes an audio-visual data stream, the link-adaptive coderunit 336 may pre-code the audio-visual data stream into varioushierarchical sets of representation data by using the scalablecapabilities of the MPEG-4 standard. In another embodiment, where theset of source data 310 includes an audio-visual data stream, thelink-adaptive coder unit 336 may pre-code the audio-visual data streaminto various hierarchical sets of representation data by using the datapartitioning capabilities of the H.264 adaptive video coding standard.Embodiments of pre-coding schemes are described more fully below.

In some embodiments, multiple pre-coding schemes may, in reality, beimplemented as multiple functions of a single pre-coding scheme. In oneembodiment, multiple scalable pre-coding schemes are implemented byusing a single MPEG-4 pre-coding algorithm to generate multiple layersof output (i.e., the generation of a base layer and enhancement layersusing MPEG-4 may be inextricably linked). In another embodiment,multiple data partitioning pre-coding schemes are implemented by usingone data partitioning algorithm to slice the set of source data 310 intomultiple data partitions. As such, it will be appreciated that phraseslike “multiple pre-coding schemes” and “a first pre-coding scheme”should be broadly construed to encompass at least single pre-codingschemes capable of producing multiple different outputs.

Embodiments of the link-adaptive coder unit 336 may associate each setof representation data with a coding and modulation scheme. For example,a first set of representation data may correspond to first-level (e.g.,low resolution) playback of the set of source data 310, and a second setof representation data may correspond to second-level (e.g., higherresolution, enhanced) playback of the same set of source data 310. Thelink-adaptive coder unit 336 may associate the first set ofrepresentation data with a lower order coding and modulation scheme(e.g., quadrature phase-shift keying with 1-to-4 forward errorcorrection (QPSK 1/4)) to better ensure the transmission of data for atleast first-level playback. The link-adaptive coder unit 336 mayassociate the second set of representation data with a higher ordercoding and modulation scheme (e.g., 8PSK 7/8), reducing the transmissionreliability of less critical enhancements for savings in power andbandwidth. Embodiments of coding and modulation schemes are describedmore fully below.

In some embodiments, the link-adaptive coder unit 336 may be configuredto tie the pre-coding functionality with the coding and modulationfunctionality. For example, certain parameters the link-adaptive coderunit 336 uses to pre-code the set of source data 310 may be determinedat least partially by the choice of coding and modulation scheme. In oneembodiment, the link-adaptive coder unit 336 determines a set of scalingparameters to use with a scalable pre-coding scheme to generate sets ofrepresentation data based on a determined coding and modulation scheme.In other embodiments, choices regarding pre-coding and/or coding andmodulation schemes may depend partially or completely on a determinationof a link condition.

In certain cases, it may be desirable to receive data representingcertain link conditions for use by the link-adaptive coder unit 336.Some embodiments of the data terminal 320 include a link awareness unit348 for receiving, generating, and/or interpreting link conditioninformation. In certain embodiments, the link awareness unit 348 isadapted to test the communication link 360 to determine its linkconditions. In other embodiments, the link awareness unit 348 is adaptedto predict or otherwise analyze link conditions based on certain priordata, stored data, and/or algorithms. In still other embodiments, thelink awareness unit 348 is adapted to receive information relating tolink conditions from an external source (e.g., from the aggregatorstation 215 of FIG. 2 over the communication link 360 via thetransceiver unit 344).

Certain embodiments of the link-adaptive coder unit 336 pass codedand/or modulated data directly to the transceiver unit 344. Otherembodiments of the link-adaptive coder unit 336 pass coded and/ormodulated data to a buffer unit 340 (e.g., any type of temporary orpermanent data store). Data stored in the buffer unit 340 may then bepassed to the transceiver unit 344. The transceiver unit 344 may processthe data into one or more signals for transmission (e.g., by bufferingor amplifying the data), and may pass the signal(s) to the communicationlink 360. The transceiver unit 344 may include any hardware, software,or other components necessary to transmit the signals or to interfacewith the communication link 360.

In some embodiments, data is transmitted by the transceiver unit 344 invarious stages. For example, a first portion of the source data 310 maybe transmitted at one time, while a second portion of the source data310 (e.g., a portion of the source data 310 stored in the buffer unit340) may be transmitted at a later time. In certain embodiments,certain, more critical elements of the source data 310 are encoded bythe link-adaptive coder unit 336 using a first pre-coding scheme andtransmitted by the transceiver unit 344 using a high-order coding andmodulation scheme. Other, less critical elements of the received sourcedata may be encoded by the link-adaptive coder unit 336 using a secondpre-coding scheme and stored in the buffer unit 340. The stored data maythen be transmitted only under certain link conditions or over a periodof time.

In these and other embodiments, signals are transmitted by the dataterminal 320 over the communication link 360 to an aggregator terminal(e.g., like the aggregator terminal 215 in FIG. 2). FIG. 4 provides asimplified block diagram of an embodiment of an aggregator terminal,according to various embodiments of the invention. The aggregatorterminal 400 may receive signals from one or more data terminals (e.g.,the data terminal 320 of FIG. 3) over one or more communications links360. Embodiments of the aggregator terminal 400 include multiplereceiver units 414 for receiving data from the multiple communicationlinks 360, and an analyzer unit 430 for processing (e.g., decode,aggregate, etc.) the signals.

In some embodiments, signals are received by the aggregator terminal 400at multiple receiver units 414. Each receiver may be the same as ordifferent from the receiver unit 324 of the data terminal 320 of FIG. 3.Each receiver units 414 is adapted to communicate with at least one dataterminal via at least one communication link 360. It is worth notingthat only a portion of the receiver units 414 may be used in certaincases. For example, an aggregator terminal 400 with eight receiver units414 may be used to communicate with only two data terminals, possiblyleaving six receiver units 414 unused.

In certain embodiments, one receiver unit 414 may be used to communicatewith multiple data terminals. For example, data from multiple dataterminals may be multiplexed over a single communication link 360 (e.g.,by OFDM, TDMA, or in some other way), or multiple communication links360 may share a single physical or logical interface (e.g., a wired orwireless communication link 360 may be logically or physicallypartitioned). In other embodiments, multiple receiver units 414 are usedfor communicating with a single data terminal. For example, a particulardata terminal may send audio information to one receiver unit 414, videoinformation to a second receiver unit 414, and location information(e.g., GPS coordinates) to a third receiver unit 414. For the sake ofadded clarity, the description will assume that each receiver unit 414is in communication with a single data terminal over a singlecommunication link 360.

In some embodiments, data received by the receiver units 414 is passeddirectly to the analyzer unit 430 for processing and/or other types ofhandling. In other embodiments, data received by the receiver units 414may be pre-processed or stored for various reasons prior to being passedto the analyzer unit 430. In certain embodiments, a decoder unit 422 isprovided in communication with each receiver unit 414 for decoding datareceived by the respective receiver unit 414. For example, each dataterminal may send data to the aggregator terminal 400 with a differentscheme for pre-coding and/or for coding and modulation. As such, it maybe desirable to decode (e.g., decode, encode, transcode, etc.) thereceived data into a common format for use by the analyzer unit 430.Embodiments of the decoder units 422 may include any hardware, software,or other components helpful for decoding data in various conditions. Forexample, the decoder units 422 may have access to various errorcorrection, de-multiplexing, formatting, and other functionality.

Embodiments of the aggregator terminal 400 may also include a pre-bufferunit 418 in communication with each receiver unit 414 for buffering dataas it is received by the respective receiver unit 414. In certainembodiments, the pre-buffer unit 418 is adapted to compensate for anytiming delays that may be created by processing incoming data by thedecoder unit 422 and or the analyzer unit 430. In other embodiments, theaggregator terminal 400 includes one or more link awareness units 426(e.g., in communication with some or all of the communication links360). In certain embodiments, the link awareness units 426 may besimilar to the link awareness unit 348 of FIG. 2. For example, a linkawareness unit 426 may test one or more of the communication links 360to determine a link condition of the communication link 360.

When data is received at the analyzer unit 430 (e.g., from one or morereceiver units 414 or decoder units 422), the analyzer unit 430 mayhandle the data in a variety of ways. In some embodiments, the analyzerunit 430 is adapted to aggregate the data into an aggregate dataset. Thedata may be aggregated in many ways, according to different types ofdesired uses for the data. In one example, it is desirable to simplycompile all the received data into a single location for futureprocessing. In another example, data representing different portions ofone set of source data (e.g., audio and video, multiple viewpoints,multiple levels of detail or definition, etc.) are received at multiplereceiver units 414. In this example, aggregating the data may includecombining and processing the data to generate a more completerepresentation of the source data. In yet another example, aggregatingthe data may include processing the incoming data (e.g., cutting andsplicing video segments, overlaying audio from one feed onto video fromanother feed, inserting an advertisement from an advertisement serverinto a live streaming video feed, etc.).

In certain embodiments, the analyzer unit 430 is in communication with adata store 450-1. The data store 450-1 may be used to store all or partof the aggregate dataset generated by the analyzer unit 430. In someembodiments, the data store 450-1 is adapted to dynamically read, write,overwrite, and otherwise manage data. The data store 450-1 may furtherbe adapted to provide data back to the analyzer unit 430 for furtherprocessing. For example, certain pre-coded layers of data may bereceived at a receiver unit 414, decoded by a decoder unit 422, andpassed through (or aggregated by) the analyzer unit 430 to the datastore 450-1. Subsequently, another pre-coded layer of the data may bereceived, and the analyzer unit 430 may retrieve the previously storedlayers of data from the data store 450-1 for further aggregation withthe new layer of data.

In some embodiments, the aggregated data is passed directly from theanalyzer unit 430 to an output unit 470 for outputting the data from theaggregator terminal 400. In other embodiments, data is passed to theoutput unit 470 from the data store 450-1. In still other embodiments,data is passed to the output unit 470 from a transcoder unit 460 orother post-processing component. For example, if data is being output toa system requiring a particular data format or transmission protocol, itmay be desirable to apply that format or protocol to the data beforepassing the data to the output unit 470. It is worth noting that theoutput unit 470 may include any components, interfaces, etc. foroutputting the data to another system or device. For example, the outputunit 470 may be adapted to output data to another data store 450-2(e.g., a server, a drive, etc.), a post-processing unit 480 (e.g., avideo editing system, a post-production system, etc.), or a network 490(e.g., the Internet).

In some embodiments, the analyzer unit 430 receives link conditioninformation from the link awareness unit(s) 426. The analyzer unit 430may use the link condition information to keep track of or predictconditions relating to some or all of the communication links 360. Forexample, the link condition information may indicate that data integrityfrom a mobile terminal communicating over a first communication link360-1 is quickly decreasing. In response, the analyzer unit 430 may takea preemptive action, like cutting the feed from that mobile dataterminal, informing another system (e.g., a production or editingsystem, a human director, etc.) of the lack of data integrity, lookingfor a similar feed from a different data terminal with high dataintegrity, etc.

It will be appreciated that there are be many circumstances in which itmay be desirable for the analyzer unit 430 to provide feedback and/orcontrol to the data terminals. As such, some embodiments of theaggregator terminal 400 include a central control unit 440 fortransmitting control signals to one or more data terminals incommunication with the aggregator terminal 400. The control signals maybe communicated to the data terminals by the central control unit 440over the same or different communication links 360 as those being usedto receive data at the aggregator terminal 400.

In one embodiment, link condition information received by the analyzerunit 430 and/or the response to that information by the analyzer unit430 is used by the central control unit 440 to generate a control signalto one or more data terminals. The control signal may signal to themobile data terminal that it is losing signal integrity, signal toanother data terminal that it should begin covering for the deficienciesof the mobile data terminal, generate automated control data forrefocusing a mobile data terminal, etc. In another embodiment, theanalyzer unit 430 determines when there is a deficiency in the contentof data (e.g., certain video angles are missing, certain levels offidelity have not yet been received, etc.). The central control unit 440may use the information to generate a control signal indicating to thedata terminals what other information is desired. In certainembodiments, the central control unit 440 or the analyzer unit 430determines how to remedy a data deficiency (e.g., from a lack of dataintegrity, a lack of content, etc.), and the central control unit 440generates the control signal according to that determination. Forexample, by knowledge of the locations and angles of a set of remotemobile cameras, it may be possible for the analyzer unit 430 todetermine how to re-point those cameras to fill in missing cameraangles. The central control unit 440 may then generate control signalsfor remotely pointing the mobile cameras accordingly. It will beappreciated that the deficiency determinations may be made in many ways,including by using automated algorithms, artificial intelligence, orhuman interfacing.

It will now be appreciated that many embodiments and configurations ofaggregator stations and data terminals are possible according to theinvention. As discussed above, some embodiments of the aggregatorstations and data terminals use certain schemes for pre-coding and/orcoding and modulating data (e.g., as part of the functionality of thelink-adaptive coder unit 336 of FIG. 3). These various schemes may befurther understood with regard to various block diagrams, like thoseshown in FIGS. 5-9. The block diagrams are purely illustrative andshould not be construed as limiting the scope of the invention.

Turning to FIG. 5A, a functional block diagram incorporating a pre-coderunit, according to various embodiments of the invention, is provided. Insome embodiments, a set of source data 535 passes to the pre-coder unit530. The pre-coder unit 530 may pre-code the set of source data 535using any number and/or type of pre-coding scheme 524.

Preferably, each pre-coding scheme 524 is different from each otherpre-coding scheme 524 in some way, generating hierarchal (or layered orpartitioned) output. Purely by way of example, some or all of thedifferent pre-coding schemes 524 may use different codecs, parameters,transformations, transcoding, algorithms, and other techniques to affectresolution, quantization, bit rate, temporality, quality, spatiality,complexity, or any other useful characteristic of the data.

In some embodiments, the pre-coder unit 530 is communicatively coupledwith a processor unit 510. In some embodiments, the processor unit 510may be part of the controller unit 240 of FIG. 2. In other embodiments,the processor unit 510 may be incorporated into the pre-coder unit 530.In still other embodiments, the processor unit 510 may be implemented asa separate component or in any other useful way. In certain embodiments,the processor unit 510 may control all or part of the functionality ofthe pre-coder unit 530. For example, where the pre-coder unit 530pre-codes the set of source data 535 based on certain parameters, theprocessor unit 510 may perform functions, including generating orselecting the parameters, instructing the pre-coder unit 530 to use theparameters, etc.

In one embodiment, three pre-coding schemes (524-1, 524-2, and 524-3)are used to generate three sets of representation data (522-1, 522-2,and 522-3), respectively. The three sets of representation data (522-1,522-2, and 522-3) may correspond to three hierarchical layers ofrepresentation of the set of source data 535. Each of these sets ofrepresentation data 522 may be stored in a representation data store520.

Further embodiments of the functionality in FIG. 5A are illustrated inthe exemplary functional block diagrams of FIGS. 5B-5D. FIG. 5B providesa functional block diagram of a set of embodiments incorporating apre-coder unit 530 using scalable pre-coding schemes 524, according tovarious embodiments of the invention.

In this set of embodiments, a set of source data 535 passes to thepre-coder unit 530. The pre-coder unit 530 pre-codes the set of sourcedata 535 using a scalable pre-coding scheme 524. Scalable pre-codingschemes 524 may divide the set of source data 535 into differenthierarchical layers. In some embodiments, a first (lowest-level) layeris called the base layer and higher layers are called enhancementlayers. A scalable pre-coding scheme 524 may intend to achieve gracefuldegradation of the picture quality. For example, by providing thecapability to playback data at a number of different levels, thepre-coding scheme 524 may avoid suffering from the “all or nothing”effect observed in some non-scalable coding systems.

In some embodiments, the scalable pre-coding scheme 524 may exploitdifferent compression techniques to produce bit streams that aredecodable at different bit rates. In one embodiment, a base layercontains the most critical information for playback that is determinedto be “good enough” for a consumer. In this embodiment, enhancementlayers may contain less critical information, like higher color depths,texturing, or resolution. Using this pre-coding scheme 524, it may bepossible to provide a consumer with more reliable access to the baselayer, such that a “good enough” level of playback is almost alwaysavailable.

It will be appreciated that various types of scalability may be used.Purely by way of example, scalabilities may include quality, temporal,spatial and complexity scalability, in order to accommodateheterogeneous networks, different devices, various link conditions, orother communication environments. Among these scalabilities, variousspatial and temporal scalable pre-coding schemes 524 may be known in theart, such as MPEG-2, MPEG-4 and H.263++. In addition, certainfine-granularity scalable (“FGS”) pre-coding schemes 524 may be known inthe art. For example, MPEG-4 standard (Part-2) may incorporate a FGStechnique with the pre-coder unit 530 using the motion-compensateddiscrete cosine transform (DCT) to generate a base layer as thelowest-level layer. Residual information between the original image andthe reconstructed base layer image may be used to form one or moreenhancement layers. An enhancement layer may be generated with a bitplane coding technique, which may provide fine granularity quality andtemporal scalabilities.

Further, in certain embodiments, scalable pre-coding schemes 524 mayprovide error correction capabilities. For example, the MPEG-4 standard(Part-2) may be used to predict base layers and enhancement layers offuture frames by using data from present frames. Using predicted data inthe context of received data may allow correction of any bit streamtruncation or lost packets, and may allow future frames to be morereliably recreated.

Regardless of the type or types of scalable pre-coding schemes 524 used,it may be preferable for each pre-coding scheme 524 to provide differentscaling results for generating hierarchal output. Further, in someembodiments, the pre-coder unit 530 may be communicatively coupled witha processor unit 510, such that the processor unit 510 may control allor part of the functionality of the pre-coder unit 530. For example, theprocessor unit 510 may be configured to generate or select scalingparameters.

In one embodiment, one pre-coding scheme 524 is used with three scalingparameters (526-1, 526-2, and 526-3) to generate three sets ofrepresentation data (522-1, 522-2, and 522-3), respectively. The threesets of representation data (522-1, 522-2, and 522-3) may correspond tothree hierarchical layers of representation of the set of source data535. For example, the first set of representation data 522-1 may includebase layer information, while the other two sets of representation data(522-2 and 522-3) may include enhancement layer information. Each ofthese sets of representation data 522 may be stored in a representationdata store 520.

FIG. 5C provides a functional block diagram illustrating a set ofembodiments of a pre-coder unit 530 using data partitioning pre-codingschemes 524, according to various embodiments of the invention. In thisset of embodiments, a set of source data 535 passes to the pre-coderunit 530. The pre-coder unit 530 pre-codes the set of source data 535using data partitioning pre-coding schemes 524. Data partitioningpre-coding schemes 524 may divide the set of source data 535 intodifferent partitions.

Various data partitioning pre-coding schemes 524 may be known in theart. For example, data partitioning capabilities may be included in theH.264/AVC (adaptive video coding) standard. According to this standard,the pre-coder unit 530 may divide the set of source data 535 into threeseparate data partitions 528.

In one embodiment, three data partitions 528 may be defined to providedifferent levels of information representing the set of source data 535.A first partition 528-1 may contain syntax elements from headerinformation within the set of source data 535, including macroblocktypes, quantization parameters, and motion vectors. A second partition528-2 may contain intra-coded block patterns and transform coefficients.The second partition 528-2 may, for example, use various spatialprediction modes to exploit spatial statistical dependencies in the setof source data 535 for a single video frame. A third partition 528-3 maycontain inter-coded block patterns and transform coefficients. The thirdpartition 528-3 may, for example, use motion vectors for block basedinter prediction to exploit block-shaped regions of each video frame inthe set of source data 535.

The information contained in the first partition 528-1 (e.g., the headerinformation of the set of source data 535) may represent a small portionof the set of source data 535, but it may be very critical to therecreation of the set of source data 535. For example, a “good enough”(or even a relatively high-quality) representation of the set of sourcedata 535 may be recreated from only the information contained in thefirst partition 528-1, like macroblock types and motion vectors. On thecontrary, information contained in the second partition 528-2 and thethird partition 528-3 may be less critical while representing largerportions of the set of source data 535. Further information contained inthe second partition 528-2 and the third partition 528-3 may be usefulonly in conjunction with information from the first partition 528-1.

It will be appreciated that other numbers and types of partitions arepossible. Further, other steps may be required or desired as part ofdata partitioning pre-coding schemes 524. Regardless of the type ortypes of data partitions 528 used, it may be preferable for eachpre-coding scheme 524 to use those data partitions 528 to providehierarchal output. Further, in some embodiments, the pre-coder unit 530may be communicatively coupled with a processor unit 510, such that theprocessor unit 510 may control all or part of the functionality of thepre-coder unit 530. For example, the processor unit 510 may beconfigured to generate or select data partitions 528.

In one embodiment, one data partitioning pre-coding schemes 524 is usedwith three data partitions 528 (528-1, 528-2, and 528-3) to generatethree sets of representation data (522-1, 522-2, and 522-3),respectively. The three sets of representation data (522-1, 522-2, and522-3) may correspond to three hierarchical partitions of the set ofsource data 535. For example, the first set of representation data 522-1may include critical header information, while the other two sets ofrepresentation data (522-2 and 522-3) may include less critical intra-and inter-coded block patterns and transform coefficients. For example,using the H.264/AVC standard, the data partitions 528 may beencapsulated into separate network abstraction layer (“NAL”) packets,which may be collated into the sets of representation data 522. Each ofthese sets of representation data 522 may be stored in a representationdata store 520.

FIG. 5D provides functional block diagram of a set of embodimentsincorporating a pre-coder unit 530 using hybrid scalable and datapartitioning pre-coding schemes 524, according to various embodiments ofthe invention. In this set of embodiments, the pre-coder unit 530pre-codes the set of source data 535 using a combination of scalable anddata partitioning pre-coding schemes 524.

In various embodiments, the scalable pre-coding schemes 524-2 and thedata partitioning pre-coding schemes 524-1 may be used in differentorders to provide the same or different results. In one embodiment, thescalable pre-coding schemes 524-2 may create base and enhancement layersof the set of source data 535, and the data partitioning pre-codingschemes 524-1 may divide some or all of those layers into differentpartitions. In another embodiment, the data partitioning pre-codingschemes 524-1 may divide the set of source data 535 into a number ofpartitions, which may then be layered using the scalable pre-codingschemes 524-2.

It will be appreciated that various scalable and data partitioningpre-coding schemes 524 may be known in the art. Further, it will beappreciated that different types of pre-coding schemes 524 may manifestvarious drawbacks. For example, many data partitioning pre-codingschemes 524-1 (e.g., H.264/AVC) may lack flexibility in the creation ofdata partitions 528. Additionally, many scalable pre-coding schemes524-2 (e.g., FGS) may degrade compression efficiencies. Somecombinations of pre-coding schemes 524 may be able to minimize some ofthese drawbacks.

In the embodiment shown in FIG. 5D, a set of source data 535 passes tothe pre-coder unit 530. The pre-coder unit 530 may use data partitioningpre-coding schemes 524-1 to divide the set of source data 535 into threedata partitions (528-1, 528-2, and 528-3). The pre-coder unit 530 maythen apply scalable pre-coding schemes 524-1 to each of the three datapartitions (528-1, 528-2, and 528-3).

In one embodiment, H.264/AVC data partitioning pre-coding schemes 524-1are used to generate the three data partitions (528-1, 528-2, and528-3). For example, as described above with respect to FIG. 5C, thefirst partition 528-1 may contain critical header and other information,while the second partition 528-2 and the third partition 528-3 maycontain less critical DCT information. Each of the three data partitions(528-1, 528-2, and 528-3) may then be passed to MPEG-4 scalablepre-coding schemes 524-2, configured with a first scaling parameter526-1 and a second scaling parameter 526-2.

In this embodiment, the first partition 528-1 may be further pre-coded,using the first scaling parameter 526-1, thereby generating a first setof representation data 522-1. The second partition 528-2 may be furtherpre-coded into two layers, using both scaling parameters (526-1 and526-2), thereby generating second and third sets of representation data(522-2 and 522-3). The third partition 528-3 may also be furtherpre-coded into two layers, using both scaling parameters (526-1 and526-2), thereby generating fourth and fifth sets of representation data(522-4 and 522-5). It will be appreciated that further pre-coding thesecond and third data partitions (528-2 and 528-3) may create layersbased on any useful characteristic of the partitioned data. For example,the base layers of the data partitions (e.g., what generated the secondand fourth sets of representation data (522-2 and 522-4)), may containcoarsely quantized DCT coefficients, while the enhancement layers of thedata partitions (e.g., what generated the third and fifth sets ofrepresentation data (522-3 and 522-5)), may contain refinementinformation from which a finer quantization can be obtained.

In some embodiments, the pre-coder unit 530 may be communicativelycoupled with a processor unit 510, such that the processor unit 510 maycontrol all or part of the functionality of the pre-coder unit 530. Incertain embodiments, the processor unit 510 may be configured togenerate or select data partitions 528. In other embodiments, theprocessor unit 510 may be configured to generate or select scalingparameters 526. In still other embodiments, the processor unit 510 maybe configured to generate or select both data partitions 528 and scalingparameters 526. It will be appreciated that the processor unit 510 maybe utilized in many ways to add capabilities and flexibility to thefunctionality of the pre-coder unit 530. For example, the datapartitioning and layering may be adjusted flexibly according to systemthroughput requirements and link conditions. To achieve greaterflexibility, the pre-coding schemes 524 may be configured to dynamicallychange numbers and types of data partitions 528, numbers and types ofscaling parameters 526, etc.

In addition to the many functions and capabilities of the pre-coder unit530, various embodiments may provide many different coding andmodulation capabilities. FIG. 6 provides an illustration of an exemplarytable of identifier data 622 for use with various embodiments of theinvention. The entries in the table of identifier data 622 show somepossible coding and modulation schemes 605 and their associatedidentifiers 610. It will be appreciated that many types of coding andmodulation are possible according to the invention. As such, the codingand modulation schemes 605 listed in the table of identifier data 622are for illustrative purposes only and should not be construed aslimiting the scope of the invention.

Each identifier 610 is associated with a coding and modulation scheme605. For example, identifier “1” 610-1 is associated with a first codingand modulation scheme 605-1, representing quadrature phase shift keyingwith a one-to-four forward error correction (FEC) rate (QPSK 1/4). Insome embodiments, each identifier 610 may be a pointer to a set ofinformation (e.g., an algorithm or a set of parameters) needed toimplement its associated coding and modulation scheme 605.

According to the table of identifier data 622, a shift from identifier“1” 610-1 to identifier “4” 610-2 maintains the same modulation order(QPSK) while increasing the information density of the FEC (from ¼ to½). The coding and modulation scheme 605-2 associated with identifier“4” 610-2 generates half as many error correction bits for eachinformation bit as does the coding and modulation scheme 605-1associated with identifier “1” 610-1.

It will be appreciated that different implementations may use differenttypes of coding and modulation schemes 605. It will further beappreciated that different tables of identifier data 622 may beconfigured to have different margins between the coding and modulationschemes 605 or to associate the identifiers 610 differently. Forexample, a table of identifier data 622 may include only every thirdentry shown on the table of identifier data 622 in FIG. 6. It willfurther be appreciated that the table of identifier data 622 may includeother types of data for various reasons, like signal quality indicators(e.g., measured signal to noise ratio, estimated signal to noise ratio,bit error rate, received power level, etc.).

When link conditions are poor (e.g., low signal-to-noise ratio), lowerorder modulation schemes and low information densities may be requiredfor reliable delivery of data. This may result in fewer data bits beingsent per unit time as well as inefficient uses of power and bandwidth.When link conditions are good, higher order modulation schemes may beused with higher information density. This may allow more data bits tobe sent per unit time with more efficient usage of power and bandwidth.

In many communication systems, the situation may be complicated by thefact that data is being sent to multiple subscribers with differentcharacteristics (e.g., in different geographic locations, havingdifferent receiving capabilities, having different entitlement levels,etc.). When data packets are addressed to a single terminal (unicast),the packets may be sent using the most efficient coding and modulationscheme 605 that the communication link will support. However, when datapackets are addressed to many receivers (multicast or broadcast), thepackets may have to be sent using the coding and modulation scheme 605that the receiver with the worst link in the group can support. Whenlink conditions affect only a portion of the subscribers (e.g., alocalized rain fade), this may result in inefficient network usage.Thus, link conditions may change dynamically per unit time, persubscriber, or based on other parameters.

By using certain adaptive coding and modulation (ACM) techniques, codingand modulation schemes 605 may be dynamically selected to match changinglink conditions. In one embodiment, coding and modulation schemes 605are selected by using the identifiers 610 and the table of identifierdata 622. The coding and modulation schemes 605 are then encapsulated,coded, mapped, and transmitted in any of a variety of ways, as known inthe art. ACM is then implemented using the DVB-S2 standard, whichspecifically provides for its use. It will be appreciated that otherimplementations are possible, for example, including systems usingDOCSIS or WiMax.

In some embodiments, the table of identifier data 622 and any otherrelated information may be stored in an identifier store 620. Theidentifier store 620 may store the table of identifier data 622 in anyuseful way. For example, the table of identifier data 622 may behard-wired into a microchip, or stored as a flat file or a relationaldatabase.

FIG. 7 provides a functional block diagram of a device 700 incorporatinga processor unit 710, a representation data store 520, and an identifierdata store 620 according to various embodiments of the invention. Insome embodiments, the device may be or may include the controller unit240 of FIG. 2.

In some embodiments, the processor unit 710 is communicatively coupledwith the representation data store 520 and the identifier data store620. The representation data store 520 may be configured to store setsof representation data 522 and the identifier data store 620 may beconfigured to store a table of identifier data 622. In certainembodiments, the processor unit 710 may be configured to process datafrom both the representation data store 520 and the identifier datastore 620 to generate a set of output data 720. In other embodiments,the processor unit 710 may be configured to control at least a portionof the generation or processing of the data stored in either or both ofthe representation data store 520 and the identifier data store 620.

The capabilities and functionality of the processor unit 710 arediscussed further in FIGS. 8A and 8B. FIG. 8A provides a functionalblock diagram incorporating a processor unit 710, according to variousembodiments of the invention. In some embodiments, the processor unit710 is the same as or is part of the controller unit 240 of FIG. 2. Theprocessor unit 710 may receive sets of representation data 522 from thepre-coder unit 530 and identifier data from the identifier data store620.

In some embodiments, the processor unit 710 may receive sets ofrepresentation data 522 from the pre-coder unit 530. The sets ofrepresentation data 522 may pass through a multiplexer unit 810. Themultiplexer unit 810 may multiplex the data in any useful way, forexample, by time division multiplexing (“TDM”), frequency divisionmultiplexing (“FDM”), wavelength division multiplexing (“WDM”), codedivision multiplexing (“CDM”), polarization, or any other effectivetechnique.

The multiplexer unit 810 may be communicatively coupled with an ACM unit820. The ACM unit 820 may be further communicatively coupled with anidentifier data store 620 and configured to receive identifier datastored at the identifier data store 620. Using the identifier data, theACM unit 820 may implement ACM on the multiplexed data coming from themultiplexer unit 810 to generate a set of output data 720.

In one embodiment, the ACM unit 820 is implemented as a single module,which is configured to accept only a single stream of data. In thisembodiment, the purpose of the multiplexer unit 810 may be to produceserial data for use by the single-stream ACM unit 820. Packets ofinformation belonging to sets of representation data 522 coming from thepre-coder unit 530 may be tagged with information that represents towhich of the sets of representation data 522 each packet belongs. Forexample, packets of data may be appended with header information thatincludes a designator number representing a particular set ofrepresentation data 522. Using the tags, the multiplexer unit 810 maymultiplex the data from the multiple sets of representation data 522 toproduce a single stream of data for the ACM unit 820.

In another embodiment, the set of source data (not shown) received bythe pre-coder unit 530 includes data for multiple source programs (e.g.,multiple video streams). At times (e.g., when link conditions aresubstantially static), the pre-coder unit 530 may be configured topre-code each of the multiple source programs into the same sets ofrepresentation data 522, using the same pre-coding schemes. For example,a set of source data for a first program and a set of source data for asecond program may each be pre-coded into a base layer and anenhancement layer. The multiplexer unit 810 may multiplex the two baselayers (i.e., one from each program) into one data stream and multiplexthe two enhancement layers into a second data stream. The two datastreams each may then pass to the ACM unit 820.

In some embodiments, the ACM unit 820 generates a set of output data720. The set of output data 720 may include one or more signalsconfigured to be transmitted over a communication link 260. The signalor signals may be coded and/or modulated as dictated by the ACM unit820. Further, the signal or signals may be coded and/or modulated in anyadditional way or combination of ways for transmission over thecommunication link 260. It will be appreciated that one or more signalsmay not be included in the set of output data. For example, at timeswhen insufficient bandwidth is available for sending multiple signals,the output data may include only one signal or only one set ofrepresentation data 522.

It will be appreciated that the processor unit 710 may be configured indifferent ways according to the invention. For example, turning to FIG.8B, another functional block diagram incorporating a processor unit,according to various embodiments of the invention, is provided. In theembodiments of FIG. 8B sets of representation data 522 coming from thepre-coder unit 530 pass through the ACM unit 820 before they aremultiplexed by the multiplexer unit 810. Three sets of representationdata (522-1, 522-2, and 522-3) may pass to the ACM unit 820. The ACMunit 820 may then use three coding and modulation schemes (822-1, 822-2,and 822-3), one on each of the three sets of representation data (522-1,522-2, and 522-3). The three coding and modulation schemes (822-1,822-2, and 822-3) may generate three output signals, which aremultiplexed by the multiplexer unit 810 to generate a set of output data720 containing a single multiplexed signal. This signal may then betransmitted over the communication link 260.

Other configurations may also be possible according to the invention. Insome embodiments, the ACM unit 820 may include a channel coding unit anda modulation unit. In one embodiment, each of the channel coding unitand the modulation unit may be independently controllable or may beconfigured to work in conjunction with one another. In anotherembodiment, the multiplexer unit 810 may multiplex multiple streams ofdata coming from the channel coding unit with different coding schemesand pass them as a single stream of data to the modulation unit.

Returning to FIG. 8A, in one embodiment, sets of representation data 522are generated by the processor unit 710 using scalable pre-codingschemes. The sets of representation data 522 may then include a baselayer and one or more enhancement layers. The layers may be multiplexedin the multiplexer unit 810 before being passed to the ACM unit 820. TheACM unit 820 may then use DVB-S2 to apply a QPSK 1/2 coding andmodulation scheme to the multiplexed data, thereby generating a QPSK 1/2signal for transmission over the communication link 260.

In some embodiments, the ACM unit 820 is further communicatively coupledto a profiler unit 830. The profiler unit 830 may be communicativelycoupled with the communication link 260 and the pre-coder unit 530. Theprofiler unit 830 may also be configured to determine certaincommunication link profiles relating to the communication link 260. Itwill be appreciated that the profiler unit 830 may generatecommunication link profiles by detecting or receiving data intrinsic toand/or extrinsic to the communication link 260, by receiving informationfrom other systems or components, or in any other useful way.

In one embodiment, the profiler unit 830 periodically or continuouslydetermines signal-to-noise ratios (“SNRs”) relating to the communicationlink 260 for use as communication link profiles. For example, theprofiler unit 830 may sample signals received at one end of thecommunication link 260 to determine the SNRs of the signals. Further,the SNRs may be recorded for statistical processing (e.g., to determineaverage SNRs or to determine SNR by signal type), for logging (e.g., tokeep a record of SNRs at different times of day or in different linkconditions), or for other reasons. It will be appreciated that the SNRsmay be detected at either end of the communication link 260 (e.g., ateither the aggregator station end or the subscriber terminal end) and byany effective method.

In another embodiment, the profiler unit 830 determines the bandwidth ofthe communication link 260 to generate a communication link profile.Similarly, the bandwidth of the communication link 260 may be providedto the profiler unit 830 manually or by another component, either beforeor when the communication link profile is generated. It will beappreciated that many other useful characteristics may be detected fromthe communication link 260 to generate communication link profiles,including, for example, throughput, hop count, path length, physicallatency, bit error rate, power consumption, power availability, excessbandwidth, traffic congestion, etc.

In yet another embodiment, the profiler unit 830 determines an audiencemetric, which may be used as a communication link profile. There may bemany ways to determine an audience metric. For example, the audiencemetric may be determined by detecting the number of subscribersreceiving a signal, the number of subscribers playing back the signal(e.g., watching the video data), polling subscribers to determine thenumber of subscribers planning to playback the signal. In someembodiments, the signal may include multicast information (informationtransmitted to subscribers who have joined the multicast stream). Inthose embodiments, the audience metric may relate to the number or typeof subscribers who have joined the multicast stream.

In still another embodiment, the profiler unit 830 may determine orreceive a receiver capability, which may be used as a communication linkprofile. In some embodiments, a subscriber terminal 230 may include areceiver for receiving signals from the communication link 260. Thereceiver may have limited capabilities, due to limitations, for example,in a port or antenna, in a playback mechanism, in a decoding mechanism,etc. For example, a subscriber may be receiving video signals on amobile phone. The phone may have a small screen with limited resolution,a small antenna with limited range, a small battery with limited power,etc.

In even another embodiment, the profiler unit 830 may determine orreceive authorization to transmit signals over the communication link260 in certain ways, which may be used as a communication link profile.In some embodiments, subscribers may have accounts with a serviceprovider, which are associated with certain entitlement information. Forexample, a subscriber may be able to purchase a base package, whichentitles the subscriber to receive and/or playback only base layerinformation generated by a scalable pre-coding scheme (e.g., alow-resolution video). Other subscribers may be able to purchase theadditional entitlement to receive and/or playback enhanced layers (e.g.,a high-definition video). In other embodiments, other parties may be atleast partially responsible for the generation of the communication linkprofiles. For example, a backbone provider may allocate certainbandwidths to certain applications at certain times of the day.

In some embodiments, the profiler unit 830 is communicatively coupledwith either or both of the ACM unit 820 and the pre-coder unit 530.Thus, in certain embodiments, the profiler unit 830 may usecommunication link profiles to determine certain parameters ofpre-coding schemes used by the pre-coder unit 530 (e.g., scalingparameters, data partitions, etc.), or to assign identifiers toappropriate coding and modulation schemes. In other embodiments, theprofiler unit 830 may generate, modify, or otherwise influence thefunctionality of both the ACM unit 820 and the pre-coder unit 530 inother ways to best suit data to various communication link profiles.

In an embodiment where the profiler unit 830 generates communicationlink profiles using an audience metric, different audience metrics maybe used in different ways. For example, the bandwidth required for apopular program may be permitted to increase at the expense of lesspopular programs. To this effect, the popular program may be encoded ata high bit rate, and sent using a very low order (reliable) modulationand coding scheme. Alternately, the least popular programs may beencoded at a low bit rate, and sent using a high order modulation andcoding scheme. In a satellite communication system according to thisembodiment, one result may include an improved balance between theoverall fixed bandwidth of the satellite transponder and service qualityand availability.

In another embodiment, the profiler unit 830 generates communicationlink profiles at least in part based on weather patterns. As the weatherworsens, link conditions may also worsen, decreasing the reliability ofdata transfers over the communication link 260. To compensate forworsening conditions, the profiler unit 830 may direct the ACM unit 820to increase transmission reliability by using higher order coding andmodulation schemes (e.g., higher order modulation schemes, lowerinformation density, etc.). The change in coding and modulation schemesmay be implemented, for example, by assigning identifiers to higherorder coding and modulation schemes in a table like the identifier datatable 622 of FIG. 6. The new assignments in the table may then be usedby the ACM unit 820 to generate the set of output data 720 fortransmission.

In yet another embodiment, the profiler unit 830 generates communicationlink profiles at least in part based on notifications generated by asubscriber terminal 230. As discussed above with reference to FIG. 3,embodiments of data terminals 230 may be configured to provide noticeson certain conditions. For example, a subscriber terminal 230 may beconfigured to store received and decoded sets of representation data 522for later playback by a subscriber. The subscriber terminal 230 mayprovide notifications, for example, when certain sets of representationdata 522 failed to be reliably received (e.g., and must be resent), whensubscribers request or subscribe to certain sets of representation data522, etc. In these and other cases, the profiler unit 830 may receive anotification and generate communication link profiles to respond tothose notifications. For example, if a set of representation data 522failed to be received, the set of representation data 522 may beretransmitted using a more reliable coding and modulation scheme.

In still another embodiment, the profiler unit 830 may generatecommunication link profiles based on a variety of different types ofdata. For example, the profiler unit 830 may receive a notification froma subscriber terminal 230 requesting retransmission of a set ofrepresentation data 522. The profiler unit 830 may poll thecommunication link 260 to determine its bandwidth, waiting to detectthat excess bandwidth is available. When excess bandwidth is availableon the communication link 260, the profiler unit 830 may direct the ACMunit 820 to retransmit the requested set of representation data 522using a very reliable (but bandwidth inefficient) coding and modulationscheme.

FIG. 9A and FIG. 9B provide an exemplary embodiment illustratingadapting coding and modulation schemes to link conditions according tovarious embodiments of the invention. In FIG. 9A, three sets ofrepresentation data (522-1, 522-2, and 522-3) pass from a pre-coder unit530 to an ACM unit 820. Based on information provided by the profilerunit 830, identifiers 610 have been assigned to coding and modulationschemes 605 in an identifier data store 620.

As illustrated, the first set of representation data 522-1 is associatedwith identifier “1” 610-1, which is further identified with a QPSK 1/4coding and modulation scheme 605-1. The second set of representationdata 522-2 is associated with identifier “2” 610-2, which is furtheridentified with a second coding and modulation scheme 605-2. The secondcoding and modulation scheme 605-2 represents the same order modulationscheme (i.e., QPSK) as the first coding and modulation scheme 605-1, butwith higher information density (i.e., 3/5 provides fewer errorcorrection bits per information bit than 1/4). The third set ofrepresentation data 522-3 is associated with identifier “3” 610-3, whichis further identified with a third coding and modulation scheme 605-3.The third coding and modulation scheme 605-3 represents a higher ordermodulation scheme than the first coding and modulation scheme 605-1(i.e., 8PSK instead of QPSK), but with the same information density(i.e., 3/5). Thus, the first set of representation data 522-1 may betransmitted with the highest reliability, relative to the other sets ofrepresentation data (522-2 and 522-3).

FIG. 9B illustrates the same embodiment of the invention, illustrativelyadapted to worsening link conditions. Still, three sets ofrepresentation data (522-1, 522-2, and 522-3) pass from a pre-coder unit530 to an ACM unit 820. Here, however, the profiler unit 830 hasdetected worsening link conditions (e.g., heavy rain). In response,identifiers 610 have been reassigned to more reliable coding andmodulation schemes 605 in the identifier data store 620.

As illustrated, the first set of representation data 522-1 is stillassociated with identifier “1” 610-1, which is still further identifiedwith a QPSK 1/4 coding and modulation scheme 605-1. No change is made tothese assignments, as the QPSK 1/4 coding and modulation scheme is themost reliable option provided in the identifier data store 620. However,the second set of representation data 522-2 associated with identifier“2” 610-2 is now further associated with a new coding and modulationscheme 605-4 (QPSK 1/2). The new coding and modulation scheme 605-4represents the same order modulation scheme (i.e., QPSK) as the secondcoding and modulation scheme 605-2 used in FIG. 9A, but with lowerinformation density (i.e., ½ instead of ⅗). Further, the third set ofrepresentation data 522-3 is re-associated with identifier “2” 610-2,further associating the third set of representation data 522-3 with thesame new coding and modulation scheme 605-4 as is associated with thesecond set of representation data 522-2. Now, the first set ofrepresentation data 522-1 may still be transmitted with the highestreliability, but the other sets of representation data (522-2 and 522-3)will also be more reliably transmitted.

The features of the various embodiments of FIGS. 1-9 may be implementedin a number of ways according to the invention. Further, the componentsand functionalities in those figures may be used to perform a number ofdifferent methods according to the invention. FIG. 10 shows anillustrative computational system for providing link awarecommunications in over communication links with changing linkconditions, according to various embodiments of the invention.

The computational system 1000 is shown having hardware elements that maybe electrically coupled via a bus 1026 (or may otherwise be incommunication, as appropriate). The hardware elements may include one ormore processors 1002, including without limitation one or moregeneral-purpose processors and/or one or more special-purpose processors(e.g., digital signal processing chips, graphics acceleration chips,encoding/decoding/transcoding chips, and/or the like); one or more inputdevices 1004 (e.g., a mouse, a keyboard, a camera, a microphone, asensor, and/or the like); and one or more output devices 1006 (e.g., adisplay device, a printer, indicators, and/or the like). In someembodiments, a link awareness unit 1034 is coupled to the bus 1026, oris otherwise accessible by other components of the computational system1000. In some embodiments, the link awareness unit 1034 provides similarfunctionality to the link awareness unit 348 of FIG. 3.

The computational system 1000 may further include (and/or be incommunication with) one or more storage devices 1008, which cancomprise, without limitation, local and/or network accessible storageand/or can include, without limitation, a disk drive, a drive array, anoptical storage device, a solid-state storage device such as a randomaccess memory (“RAM”), and/or a read-only memory (“ROM”), which can beprogrammable, flash-updateable, and/or the like.

The computational system 1000 might also include a communicationssubsystem 1014, which can include without limitation a modem, a networkcard (wireless or wired), an infra-red communication device, a wirelesscommunication device and/or chipset (such as a Bluetooth device, an802.11 device, a WiFi device, a WiMax device, cellular communicationfacilities, etc.), and/or the like. The communications subsystem 1014may permit data to be exchanged with a communication link 1020 (e.g.,like the communication link 360 of FIG. 3), and/or any other devicesdescribed herein. In many embodiments, the computational system 1000will further comprise a working memory 1018, which can include a RAM orROM device, and/or one or more buffers, as described above.

The computational system 1000 also may include software elements, shownas being currently located within the working memory 1018, including anoperating system 1024 and/or other code, such as one or more applicationprograms 1022, which may include computer programs of the invention,and/or may be designed to implement methods of the invention and/orconfigure systems of the invention, as described herein. For example,the application programs 1022 may include functionality to implementsome or all of the aspects of a transcoder unit 1030 (e.g., like thetranscoder unit 328 of FIG. 3) and/or a link-adaptive coder unit 1032(e.g., like the link-adaptive coder unit 336 of FIG. 3). It is worthnoting, that any of the functionality described as software elements mayadditionally or alternatively be implemented in firmware, hardware, orother implementations. For example, the link-adaptive coder unit 1032may be alternatively implemented as an application-specific functionalblock electrically coupled with the bus 1026.

Merely by way of example, one or more procedures described with respectto the method(s) discussed above might be implemented as code and/orinstructions executable by a computer (and/or a processor within acomputer). A set of these instructions and/or code might be stored on acomputer readable storage medium 1010 b. In some embodiments, thecomputer readable storage medium 1010 b is the storage device(s) 1008described above. In other embodiments, the computer readable storagemedium 1010 b might be incorporated within a computational system, suchas the system 1000. In still other embodiments, the computer readablestorage medium 1010 b might be separate from the computational system(i.e., a removable medium, such as a compact disc, etc.), and/orprovided in an installation package, such that the storage medium can beused to configure a general purpose computer with the instructions/codestored thereon. These instructions might take the form of executablecode, which is executable by the computational system 1000 and/or mighttake the form of source and/or installable code, which, upon compilationand/or installation on the computational system 1000 (e.g., using any ofa variety of generally available compilers, installation programs,compression/decompression utilities, etc.), then takes the form ofexecutable code. In these embodiments, the computer readable storagemedium 1010 b may be read by a computer readable storage media reader1010 a.

In one embodiment, the invention employs the computational system toperform methods of the invention. According to a set of embodiments,some or all of the procedures of such methods are performed by thecomputational system 1000 in response to processor 1002 executing one ormore sequences of one or more instructions (which might be incorporatedinto the operating system 1024 and/or other code, such as an applicationprogram 1022) contained in the working memory 1018. Such instructionsmay be read into the working memory 1018 from another machine-readablemedium, such as one or more of the storage device(s) 1008 (or 1010).Merely by way of example, execution of the sequences of instructionscontained in the working memory 1018 might cause the processor(s) 1002to perform one or more procedures of the methods described herein. Inthis way, the computational system 1000 can be “configured to,”“operable to,” and/or “adapted to” perform any number of such proceduresor methods.

The terms “machine readable medium” and “computer readable medium,” asused herein, refer to any medium that participates in providing datathat causes a machine to operate in a specific fashion. In an embodimentimplemented using the computational system 1000, variousmachine-readable media might be involved in providing instructions/codeto processor(s) 1002 for execution and/or might be used to store and/orcarry such instructions/code (e.g., as signals). In manyimplementations, a computer readable medium is a physical and/ortangible storage medium. Such a medium may take many forms, includingbut not limited to, non-volatile media, volatile media, and transmissionmedia. Non-volatile media includes, for example, optical or magneticdisks, such as the storage device(s) (1008 or 1010). Volatile mediaincludes, without limitation dynamic memory, such as the working memory1018. Transmission media includes coaxial cables, copper wire, and fiberoptics, including the wires that comprise the bus 1026, as well as thevarious components of the communication subsystem 1014 (and/or the mediaby which the communications subsystem 1014 provides communication withother devices). Hence, transmission media can also take the form ofwaves (including without limitation radio, acoustic and/or light waves,such as those generated during radio-wave and infra-red datacommunications).

Common forms of physical and/or tangible computer readable mediainclude, for example, a floppy disk, a flexible disk, a hard disk,magnetic tape, or any other magnetic medium, a CD-ROM, any other opticalmedium, punchcards, papertape, any other physical medium with patternsof holes, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other memory chipor cartridge, a carrier wave as described hereinafter, or any othermedium from which a computer can read instructions and/or code.

Various forms of machine-readable media may be involved in carrying oneor more sequences of one or more instructions to the processor(s) 1002for execution. Merely by way of example, the instructions may initiallybe carried on a magnetic disk and/or optical disc of a remote computer.A remote computer might load the instructions into its dynamic memoryand send the instructions as signals over a transmission medium to bereceived and/or executed by the computational system 1000. Thesesignals, which might be in the form of electromagnetic signals, acousticsignals, optical signals, and/or the like, are all examples of carrierwaves on which instructions can be encoded, in accordance with variousembodiments of the invention.

The communications subsystem 1014 (and/or components thereof) generallymay receive the signals, and the bus 1026 then may carry the signals(and/or the data, instructions, etc. carried by the signals) to theworking memory 1018, from which the processor(s) 1002 may retrieve andexecute the instructions. The instructions received by the workingmemory 1018 may optionally be stored on a storage device 1008 eitherbefore or after execution by the processor(s) 1002.

It will be apparent to those skilled in the art that substantialvariations may be made in accordance with specific requirements. Forexample, customized hardware might also be used, and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets, etc.), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.

It will be appreciated that various methods are possible, according tovarious embodiments of the invention. In some embodiments, the methodsmay be implemented by one or more systems, including but not limited tothose described above. FIG. 11 provides a flow diagram describingmethods for receiving source data and transmitting the source data overa communication link having changing link conditions, according tovarious embodiments of the invention.

The method 1100 begins at block 1104 by receiving source data from adata source. At block 1108, a portion (e.g., some or all) of the sourcedata is stored as a first representation dataset representing the sourcedata. At least a portion of the source data may be pre-coded at block1112 using a first pre-coding scheme to generate a second representationdataset. The second representation dataset may be decodable to provide aset of first-level playback data representing the source data.Typically, the second representation dataset may be different from thefirst representation dataset. In some embodiments, a portion of thesource data and/or a portion of the first representation dataset ispre-coded at block 1116 using a second pre-coding scheme to generate aset of representation data, decodable in combination with the secondrepresentation dataset to provide a set of second-level playback datarepresenting the set of source data.

For example, a video stream may be received at block 1104. Ahierarchical pre-coding scheme may generate a base layer at block 1112.At the same time, the hierarchical pre-coding scheme may generate one ormore enhancement layers at block 1116. Alternately, a portion of thevideo stream may be stored at block 1104 (either prior to, during, orsubsequent to the pre-coding at block 1108). This stored data may thenbe pre-coded to generate the enhancement layers at block 1116.

At block 1120, a link condition may be generated, defining a conditionof the communication link. For example, the link condition may relate tothe bandwidth, latency, data integrity, bit error rate, etc. of thecommunication link. In some embodiments, all or part of the informationused in block 1120 to generate the link condition is received from anexternal system or device (e.g., an aggregator system) at block 1124. Inother embodiments, the link condition is determined by some othermethod, for example by testing the communication link for certainparameters.

The second representation dataset may be encoded at block 1128 into anencoded data signal as a function of the link condition generated inblock 1120. In some embodiments, encoding the second representationdataset at block 1128 includes associating the first representationdataset and/or the second representation dataset with one or more codingand modulation schemes. In certain embodiments, the coding and/ormodulation schemes are determined as a function of the link condition.For example, a base layer may be encoded using a high-order coding andmodulation scheme, and an enhancement layer may be encoded using alower-order coding and modulation scheme.

At block 1132, the encoded data signal may be transmitted over thecommunication link. In some embodiments, transmitting the encoded datasignal at block 1132 occurs in stages. For example, the firstrepresentation dataset may be transmitted over the communication link atblock 1132 when the link condition substantially matches a first linkcondition profile; and the second representation dataset may betransmitted over the communication link at block 1132 when the linkcondition substantially matches a second link condition profile. Incertain embodiments, the encoded data signal is transmitted according tothe coding and modulation scheme associated with the dataset (e.g., atblock 1128.

The encoded signal(s) transmitted over communication links may bereceived, decoded, and/or aggregated. FIG. 12 provides a flow diagramdescribing methods for aggregating data received over communicationlinks having changing link conditions, according to various embodimentsof the invention. In some embodiments, the received and aggregated datawas generated and transmitted by a method similar to the method 1100 ofFIG. 11.

The method 1200 begins at block 1204 by receiving a first encoded datasignal from a first data system over a first communication link. Thefirst encoded data signal may have been encoded by the first data systemusing a first encoding scheme as a function of a first link conditiondefining a condition of the first communication link. At block 1208, asecond encoded data signal is received. In some embodiments, receiving asecond encoded data signal at block 1208 includes receiving the secondencoded data signal from a second data system over a secondcommunication link. The second encoded data signal may have been encodedby the second data system using a second encoding scheme as a functionof a second link condition defining a condition of the secondcommunication link.

At block 1212, a portion of the first encoded data signal and a portionof the second encoded data signal may be aggregated to generate anaggregate dataset. The aggregate dataset may be analyzed at block 1216to make a data deficiency determination. The method may generate acontrol signal at block 1220 as a function of the data deficiencydetermination. At block 1224, the control signal may be transmitted tothe first data system (and/or the second data system), the controlsignal being adapted to affect operation of the first data system.

It should be noted that the methods, systems, and devices discussedabove are intended merely to be examples. It must be stressed thatvarious embodiments may omit, substitute, or add various procedures orcomponents as appropriate. For instance, it should be appreciated that,in alternative embodiments, the methods may be performed in an orderdifferent from that described, and that various steps may be added,omitted, or combined. Also, features described with respect to certainembodiments may be combined in various other embodiments. Differentaspects and elements of the embodiments may be combined in a similarmanner. Also, it should be emphasized that technology evolves and, thus,many of the elements are exemplary in nature and should not beinterpreted to limit the scope of the invention.

Specific details are given in the description to provide a thoroughunderstanding of the embodiments. However, it will be understood by oneof ordinary skill in the art that the embodiments may be practicedwithout these specific details. For example, well-known circuits,processes, algorithms, structures, and techniques have been shownwithout unnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that the embodiments may be described as a processwhich is depicted as a flow diagram or block diagram. Although each maydescribe the operations as a sequential process, many of the operationscan be performed in parallel or concurrently. In addition, the order ofthe operations may be rearranged. A process may have additional stepsnot included in the figure.

Moreover, as disclosed herein, the term “memory” or “memory unit” mayrepresent one or more devices for storing data, including read-onlymemory (“ROM”), random access memory (“RAM”), magnetic RAM, core memory,magnetic disk storage mediums, optical storage mediums, flash memorydevices or other computer-readable mediums for storing information. Theterm “computer-readable medium” includes, but is not limited to,portable or fixed storage devices, optical storage devices, wirelesschannels, a sim card, other smart cards, and various other mediumscapable of storing, containing, or carrying instructions or data.

Further, it will be appreciated that other and different components maybe incorporated into or used by the devices and systems describedherein, and functions of the various devices, systems, and componentsmay be implemented in a number of ways. For example, the functionsvarious components may be implemented in hardware, software, orfirmware. Implementations of these functions may include one or moreApplication Specific Integrated Circuits (“ASICs”) adapted to perform asubset of the applicable functions in hardware. Alternatively, thefunctions may be performed by one or more other processing units (orcores), on one or more integrated circuits. In other embodiments, othertypes of integrated circuits may be used (e.g., Structured/PlatformASICs, Field Programmable Gate Arrays (“FPGAs”) and other Semi-CustomICs), which may be programmed in any manner known in the art. Each mayalso be implemented, in whole or in part, with instructions embodied ina computer-readable medium, formatted to be executed by one or moregeneral or application specific processors. Thus, the devices andsystems may include different types and configurations of memory, whichmay be integrated into the hardware or may be one or more separatecomponents.

Furthermore, embodiments may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middleware,or microcode, the program code or code segments to perform the necessarytasks may be stored in a computer-readable medium such as a storagemedium. Processors may perform the necessary tasks.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. For example, the above elements may merely be a component ofa larger system, wherein other rules may take precedence over orotherwise modify the application of the invention. Also, a number ofsteps may be undertaken before, during, or after the above elements areconsidered. Accordingly, the above description should not be taken aslimiting the scope of the invention.

What is claimed is:
 1. A link-aware gateway system for communicatingdata to a plurality of subscriber terminals over at least onecommunication link with changing link conditions, the system comprising:a receiver unit that receives a set of source data representing mediacontent; a profiler unit, executed by one or more processors, thatdetermines an audience metric related to the media content received atthe receiver unit; a link awareness unit, executed by one or moreprocessors, adapted to generate a link condition defining a condition ofthe at least one communication link; an adaptive coder unit,communicatively coupled with the receiver unit, the profiler unit, andthe link awareness unit, and adapted to encode the source data into anencoded data signal as a function of the link condition and the audiencemetric; and a transceiver unit, communicatively coupled with theadaptive coder unit, and adapted to transmit the encoded data signalover the at least one communication link.
 2. The system of claim 1,wherein the adaptive coding unit comprises a precoder unit that isoperative to precode the source data based on the audience metric andaccording to a progressive encoding scheme such that the media contentis represented by at least first-level playback data and second-levelplayback data, such that playback of the media content is at a firstfidelity using only the first-level playback data and playback of themedia content is at a second fidelity by combining the first-levelplayback data and the second-level playback data, the second fidelitybeing higher than the first fidelity.
 3. The system of claim 2, whereinthe profiler unit is operative to generate a communication link profilefor the at least one communication link at least in part based on theaudience metric.
 4. The system of claim 3, wherein the receiver unitreceives a first set of source data for a first media content thatcorresponds with a popular program as reflected in the audience metricfor the first media content and a second set of source data for a secondmedia content that corresponds with a less popular program relative tothe first media content as reflected in the audience metric.
 5. Thesystem of claim 4, wherein the adaptive coder unit is configured toassociate the first set of source data with a first coding andmodulation scheme and to associate the second set of source data with asecond coding and modulation scheme, wherein the first coding andmodulation scheme is of a lower order than the second coding andmodulation scheme.
 6. The system of claim 5, wherein the transceiverunit is configured to transmit a first signal comprising the first setof source data over the at least one communication link using the firstcoding and modulation scheme and is configured to transmit a secondsignal comprising the second set of source data over the at least onecommunication link using the second coding and modulation scheme.
 7. Thesystem of claim 6, wherein the first signal comprises first-levelplayback data and second-level playback data for the first set of sourcedata and the second signal only includes first-level payback data forthe second set of source data, the first signal being a higher bandwidthsignal than the second signal.
 8. A method for communicating data to aplurality of subscriber terminals over at least one communication linkwith changing link conditions in a link-aware gateway system, the methodcomprising: receiving a set of source data representing media content;determining an audience metric related to the media content; generatinga link condition defining a condition of the at least one communicationlink; encoding the source data into an encoded data signal as a functionof the link condition and the audience metric; and transmitting theencoded signal over the at least one communication link.
 9. The methodof claim 8, further comprising: precoding the source data based on theaudience metric and according to a progressive encoding scheme such thatthe media content is represented by at least first-level playback dataand second-level playback data, such that playback of the media contentis at a first fidelity using only the first-level playback data andplayback of the media content is at a second fidelity by combining thefirst-level playback data and the second-level playback data, the secondfidelity being higher than the first fidelity.
 10. The method of claim9, further comprising: generating a communication link profile for theat least one communication link at least in part based on the audiencemetric.
 11. The method of claim 10, wherein the receiving includesreceiving a first set of source data for a first media content thatcorresponds with a popular program as reflected in the audience metricfor the first media content and a second set of source data for a secondmedia content that corresponds with a less popular program relative tothe first media content as reflected in the audience metric.
 12. Themethod of claim 11, further comprising: associating the first set ofsource data with a first coding and modulation scheme; and associatingthe second set of source data with a second coding and modulationscheme; wherein the first coding and modulation scheme is of a lowerorder than the second coding and modulation scheme.
 13. The method ofclaim 12, wherein the transmitting includes transmitting a first signalcomprising the first set of source data over the at least onecommunication link using the first coding and modulation scheme andtransmitting a second signal comprising the second set of source dataover the at least one communication link using the second coding andmodulation scheme.
 14. The system of claim 13, wherein the first signalcomprises first-level playback data and second-level playback data forthe first set of source data and the second signal only includesfirst-level payback data for the second set of source data, the firstsignal being a higher bandwidth signal than the second signal.
 15. Oneor more non-transitory processor-readable storage media embodied withinstructions for executing on one or more processors and circuits of adevice a process for communicating data to a plurality of subscriberterminals over at least one communication link with changing linkconditions in a link-aware gateway system, the process comprising:receiving a set of source data representing media content; determiningan audience metric related to the media content; generating a linkcondition defining a condition of the at least one communication link;encoding the source data into an encoded data signal as a function ofthe link condition and the audience metric; and transmitting the encodedsignal over the at least one communication link.
 16. The one or morenon-transitory processor-readable storage media of claim 15, furthercomprising: precoding the source data based on the audience metric andaccording to a progressive encoding scheme such that the media contentis represented by at least first-level playback data and second-levelplayback data, such that playback of the media content is at a firstfidelity using only the first-level playback data and playback of themedia content is at a second fidelity by combining the first-levelplayback data and the second-level playback data, the second fidelitybeing higher than the first fidelity.
 17. The one or more non-transitoryprocessor-readable storage media of claim 16, further comprising:generating a communication link profile for the at least onecommunication link at least in part based on the audience metric. 18.The one or more non-transitory processor-readable storage media of claim17, wherein the receiving includes receiving a first set of source datafor a first media content that corresponds with a popular program asreflected in the audience metric for the first media content and asecond set of source data for a second media content that correspondswith a less popular program relative to the first media content asreflected in the audience metric.
 19. The one or more non-transitoryprocessor-readable storage media of claim 18, further comprising:associating the first set of source data with a first coding andmodulation scheme; and associating the second set of source data with asecond coding and modulation scheme; wherein the first coding andmodulation scheme is of a lower order than the second coding andmodulation scheme.
 20. The one or more non-transitory processor-readablestorage media of claim 19, wherein the transmitting includestransmitting a first signal comprising the first set of source data overthe at least one communication link using the first coding andmodulation scheme and transmitting a second signal comprising the secondset of source data over the at least one communication link using thesecond coding and modulation scheme.
 21. The one or more non-transitoryprocessor-readable storage media of claim 20, wherein the first signalcomprises first-level playback data and second-level playback data forthe first set of source data and the second signal only includesfirst-level payback data for the second set of source data, the firstsignal being a higher bandwidth signal than the second signal.